High-salt in addition to high-fat diet may enhance inflammation and fibrosis in liver steatosis induced by oxidative stress and dyslipidemia in mice

Yuzaburo Uetake, Hitoshi Ikeda, Rie Irie, Kazuaki Tejima, Hiromitsu Matsui, Sayoko Ogura, Hong Wang, ShengYu Mu, Daigoro Hirohama, Katsuyuki Ando, Tatsuya Sawamura, Yutaka Yatomi, Toshiro Fujita, Tatsuo Shimosawa

It is widely known that salt is an accelerating factor for the progression of metabolic syndrome and causes cardiovascular diseases, most likely due to its pro-oxidant properties. We hypothesized that excessive salt intake also facilitates the development of nonalcoholic steatohepatitis (NASH), which is frequently associated with metabolic syndrome. We examined the exacerbating effect of high-salt diet on high-fat diet-induced liver injury in a susceptible model to oxidative stress, apoE knockout and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) transgenic mice. High-salt diet led to NASH in high-fat diet-fed LOX-1 transgenic/apoE knockout mice without affecting high-fat diet-induced dyslipidemia or hepatic triglyceride accumulation. Additionally, a high-salt and high-fat diet stimulated oxidative stress production and inflammatory reaction to a greater extent than did a high-fat diet in the liver of LOX-1 transgenic/apoE knockout mice. We demonstrated that high-salt diet exacerbated NASH in high-fat diet-fed LOX-1 transgenic /apoE knockout mice and that this effect was associated with the stimulation of oxidative and inflammatory processes; this is the first study to suggest the important role of excessive salt intake in the development of NASH.